1. Field of the Invention
The present invention relates to a video display apparatus.
2. Description of the Related Art
The following Japanese patent application publications provide examples of conventional video display apparatus.
JP 10-322622 describes a digital television broadcast receiver that receives information indicating the type or genre of a television program and sets different audio and video output parameters for different genres, according to user preferences. The type or genre information is included in program guidance information broadcast by the broadcasting station together with the program data in digital broadcasts, including broadcasts from earth-orbiting satellites.
A problem with this scheme is that the necessary program guidance information is not present in conventional analog broadcasts, and is also missing from recorded programs obtained from an external device such as a digital versatile disc (DVD) device. Another problem is that even when the program guidance information is present, it does not necessarily characterize the entire content of the program. A movie program, for example, may have interspersed commercial segments. Although these segments are quite different in character from the movie content, they are classified by the program guidance information as part of the movie.
JP 2002-520747 discloses a method of characterizing video content by identifying key video frames, creating histograms from the key frames, and classifying the histograms. The purpose, however, is to determine the boundaries between programs in order to construct an index of the video contents, not to adjust video output parameters according to the type of video content. In some cases, the classification scheme would lead to parameters that produce video characteristics inappropriate for the video content.
JP 2004-7301 describes an image processing apparatus that creates a histogram of the luminance signal in an input video signal to derive a relationship between luminance and appearance frequency and modifies the video signal to improve the picture quality, selecting a gradation pattern suitable for the video picture. This scheme, however, does not attempt to classify video content or adjust video output parameters according to such a classification. In some cases, the video display characteristics of the modified video signal are inappropriate for the differing contents of different programs.